busybox: fix tar

[awiouy]

Busybox tar fails to untar some files with "bad tar magic"/"short read".
This problem also occurs on other Busybox distributions, eg Alpine, OpenWrt, etc.
I could not find a bug report/fix, only a a workaround: install tar.
There are probably other things to do, ie disable Busybox tar and install tar, but I would not know what.

[lrusak]

You can add this to an add-on that needs it, but I don't think this should go in the base system

[awiouy]

If you do not mind, I will leave that here until Busybox tar is fixed.
https://bugs.busybox.net/show_bug.cgi?id=9406

[awiouy]

Busybox provided a patch to fix tar, see bug 9406 linked above.
The patch applies and builds, needs to be runtime tested.
@MilhouseVH could you add this to your builds for testing?

[MilhouseVH]

OK (will be in #1111)

Edit: BTW this is the commit: https://git.busybox.net/busybox/commit/?id=9655f95d0f501b03b33c7896b7b0c23d090aff81

I've tested your tar.gz file from 9406 on RPi3 with build #1111 and I'm not seeing any tar errors now, so the fix looks good. :)

[awiouy]

Cool, thank you for having tested.
Ready to merge